Proposed changes to the ACT's electoral boundaries for the Legislative Assembly could cause a major shake-up of Territory politics.

The ACT Legislative Assembly is made up of 17 members drawn from two five member electorates and one seven member electorate.

Under the Augmented ACT Electoral Commission proposal, Ginninderra would gain two new members while Molonglo would lose two.

ABC election analyst Antony Green says this could cost the Greens their fourth seat in the Assembly at the next election.

"For the Greens to retain their fourth seat, they will now need to win a second seat in Ginninderra, but the Green vote is not nearly as strong in Ginninderra as in Molonglo," he said.

"The Greens elected a Ginninderra member from 0.83 quotas in 2008, and while the new seven-member constituency means they will achieve a quota in their own right, the Greens will be well short of a second quota.

"On 2008 results, Labor gains one of the new seats winning a third seat in Ginninderra while the Liberals stay at two and the Greens retain their one seat.

"Who would win the seventh seat in Ginninderra is impossible to determine based on 2008 results."

But ACT Electoral Commissioner Phil Green says the changes are not set in stone.

"It is possible that people will have objections to this proposal so there is now a four week objection period," he said.

"People have got up until the 5th of August to object to this current proposal.

"The Augmented Commission will consider any objections to this proposal. It's then got the opportunity to either accept or reject this proposal it would indeed make a different proposal if another proposal did emerge from the public submissions."